Fighting Broken Symmetry with Doping: Toward Polar Resonant Tunneling Diodes with Symmetric Characteristics
Fighting Broken Symmetry with Doping: Toward Polar Resonant Tunneling Diodes with Symmetric Characteristics
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DOI：
10.1103/physrevapplied.13.034048
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发表时间：
2020-03-19
影响因子：
4.6
通讯作者：
Xing, Huili Grace
中科院分区：
文献类型：
--
作者：
Encomendero, Jimy;Protasenko, Vladimir;Xing, Huili Grace
最近在氮化半导体中共振隧道输运的演示，使得利用这种量子输运机制进行实际应用的努力更加活跃。然而，在极性半导体中，固定极化电荷和移动自由载流子之间的相互作用导致了不对称输运特性。在这里，我们研究了利用简并掺杂的接触层来屏蔽内置偏振场和恢复对称谐振注入的可能性。由于高掺杂密度，GaN/AlN谐振隧道二极管（rtd）在两个偏置极性下都观察到负差分电导。此外，由于掺杂的溶解度限制，我们的分析模型揭示了均匀掺杂所达到的最小共振隧穿电压的下界。通过阻抗测量研究了电荷存储动力学，表明在接近平衡的条件下，极性rtd有效地表现为并联板电容器。我们的分析模型完全再现了这些机制，为极性共振隧穿器件的设计和分析提供了一个有用的理论框架。
The recent demonstration of resonant tunneling transport in nitride semiconductors has led to an invigorated effort to harness this quantum transport regime for practical applications. In polar semiconductors, however, the interplay between fixed polarization charges and mobile free carriers leads to asymmetric transport characteristics. Here, we investigate the possibility of using degenerately doped contact layers to screen the built-in polarization fields and recover symmetric resonant injection. Thanks to a high doping density, negative differential conductance is observed under both bias polarities of GaN/AlN resonant tunneling diodes (RTDs). Moreover, our analytical model reveals a lower bound for the minimum resonant-tunneling voltage achieved via uniform doping, owing to the dopant solubility limit. Charge storage dynamics is also studied by impedance measurements, showing that at close-to-equilibrium conditions, polar RTDs behave effectively as parallel-plate capacitors. These mechanisms are completely reproduced by our analytical model, providing a theoretical framework useful in the design and analysis of polar resonant-tunneling devices.